The Annual Course on Principles of STD and HIV Research was first held in 1993 to provide an intensive overview of skills needed to pursue a research career in the field of STD/HIV. Since then, approximately 1900 trainees have attended the course, including many women and racial/ethnic minority students. Increasingly, an interdisciplinary approach has become essential in designing studies and in obtaining funding for STD/HIV research. Establishing familiarity with research perspectives outside one's own discipline provides young investigators with tools for continued interdisciplinary learning and collaboration, and for maintaining a broad scope of investigative possibilities. This course offers a unique opportunity for introductory training in behavioral, clinical, epidemiologic, statistical, operational, and basic science research by providing a practically oriented overview of language and skills common to these broad disciplines. Course duration is limited to two weeks to encourage individuals who are establishing active research careers and allow those who reside outside of the local area to attend. In addition, an on-line version of the course has been developed to expand our reach to international sites for asynchronous group learning. Course objectives are to: 1) Introduce young investigators to critical research areas and emerging questions in the field of STD/HIV; 2) Expose investigators to research techniques and tools needed to conduct scientifically and ethically sound studies, including study design, experimental approach, development of instruments for data collection, human subjects considerations, and data analysis; 3) Teach trainees the fundamentals of different disciplines involved in STD/HIV research in order to foster research collaborations; and 4) Discuss strategies for successfully finding a mentor, competing for research funds and publishing one's work. The course integrates six tracks: 1) Essentials of STD/HIV interdisciplinary research; 2) Clinical and epidemiologic aspects of specific infections; 3) Pathogenesis of specific infections; 4) Behavioral research methods and research in special populations; 5) Operational research and health economics; and 6) Strategies for successful and ethical research. The course proceedings are disseminated on a participant website with access restricted to registered students. The course website contains learning objectives, speakers' slides, audio recordings of lectures, and key references.